More Near-Disasters Like Oroville Are Very Likely in the Future, Say Experts

Despite increasing evidence of climate impacts, state isn’t considering climate change for new dams and water storage projects that are in the works

Maureen Nandini Mitra

February 21, 2017

As the skies continued to open up over the past few days and evacuations were being ordered in many parts of Northern California, like many others in this state, I couldn’t but wonder if other dams in California could run into the same kind of problems as Oroville dam in Butte County, where heavy rainfall during what’s turning out to be California’s wettest season on record, surpassed the dam’s capacity.

Photo by Photo by Cal OESThe 770-foot-tall dam Oroville Dam in northern California, the nation’s tallest, ran into problems with both it’s main and emergency spillways, prompting the evacuation of nearly 200,000 people living in low-lying communities downstream on February 12.

To recap: The 770-foot-tall dam, the nation’s tallest, ran into problems with both it’s main and emergency spillways, prompting the evacuation of nearly 200,000 people living in low-lying communities downstream on February 12. The dam’s water level has dropped since then and most people have returned home. But they have been told to remain vigilant given more rains are predicted for California this winter. Meanwhile, as of yesterday, numerous other reservoirs across the state are almost at capacity.

California has always alternated between periods of drought and extreme precipitation that can lead to massive flooding. But the key difference now is that climate change is intensifying the risk of floods and mudslides by inducing even more erratic and intense precipitation events. Can our state’s more than 1,400 dams withstand the pressure of these changing climate patterns? What needs to be done to ensure there aren’t similar problems as Oroville’s with other dams? What about the new dam projects or reservoir expansion projects that are being planned? Are they going to be climate ready?

To help shed some light on these questions I recently spoke with water experts Deborah Moore and Eric Wesselman. More was a commissioner with the World Commission on Dams, an international body that investigated the performance of dam projects across the world. She’s also a board member of International Rivers, an organization that works to protect rivers and the rights of communities that depend on them. Wesselman is executive director of Friends of the River, which works to protect and restore California Rivers by influencing public policy and inspiring citizen action. The main takeaway from our multiple conversations — over the phone and during Terra Verde, a radio show I co-host once a month — near-disasters (or worse) like Oroville are very likely in the future because most of our aging dams and reservoirs aren’t ready to handle the kind of deluge that’s going to be the new normal. On the positive side, we have the knowledge and the tools to build more climate resilient water infrastructure. Here’s a brief excerpt from our conversations.

Maureen: Deborah, you mentioned that what happened up at Oroville was a manmade disaster. Could you elaborate on that?

People are referring to this as a natural disaster because of the floods and heavy rainfall that we are having, that’s the nature part, but really the dam and what’s happening with it is human-made. How the dams are interacting with our changing precipitation patterns is really a human caused problem. And on top of that you also figure that the change climate change is causing is also largely due to humans.

We have this idea that we can control nature and control rivers, and dams are part of this idea. But as we are seeing with more extreme weather patterns due to climate change, we have to question what our ability to control these are and how we can better collaborate with nature.

Eric, do you think California’s network of more than 1,400 dams is in good shape? Can they withstand the kind of weather onslaught that put Oroville at risk? I believe some of them are more than 40 to 50 years old?

Clearly we need to be doing an assessment of the current water infrastructure in the state and find those where improvements do need to be made to make them for downstream communities. At the same time we have dams and levees that just aren’t meeting the need any more, that aren’t in the public interest and should be decommissioned. Like the dams on the Klamath and on the Yuba rivers, and the Searsville dam on San Francisquito Creek In Palo Alto. There are a number of dams with similar spillway problems [as Oroville], or where the inflow can exceed what you can release as outflow out of the dam and that puts them in a dangerous situation. There’s some water purveyors that are looking at new water projects that would make it even worse, like the Merced Irrigation District, which wants to raise the emergency spillway at Exchequer Dam on the Merced River so that it could store more water, but that would further reduce their ability to manage the reservoir during a flood event like this.

We really need to start taking stock of the situation. Now is the time to be preparing for a future when climate change is taking hold, we need to start addressing it in new and creative 21st century ways and working with nature – looking and flood control and water storage solutions that help us meet our water needs in a sustainable fashion that reduces our risks and makes us more resilient in the face of climate change.

But we are still planning to build more dams or expand existing water storage facilities, right? The $7.5 billion water bond that voters approved in 2014 sets aside $2.7 billion in building or expanding water storage structures. It’s my understanding that the designing and building of these new, public-funded projects don’t require an analysis of more extreme weather events. Is that right, Deborah?

These new water projects are not going to require the proposals include future climate scenarios. The California Water Commission has received numerous technical comments and expert advice that they should do so, but as of December 2016 the Commission decided to not require that. However, I think the water community and people who have been tracking this topic have heard some noises from the department of water resources just in the last couple of weeks since this crisis started, saying, oh, maybe we need to rethink that.

Photo by David/Flickr There’s some debate about whether we need new water capture and storage facilities at all. Research by the Pacific Institute has shown that California could save up to 14 million acre-feet a year of untapped water through water saving practices, recycling and storm water capture.

Could you give an example of what they should be looking at in terms of incorporating climate science in engineering design?

Moore: What civil engineers typically do when planning for dams, is they use historic data on river flows and precipitation patterns to try to predict how much water is anticipated in a typical year. In addition they plan for what they consider certain kinds of extreme events, like one in a 100-years-flood or one in 500-years-flood. They design infrastructure using this historic data, and they call this “stationarity.” Now you can Google “stationarity” and there are numerous academic papers saying, “stationarity is dead.” We can no longer use historic data in order to plan these projects because it’s no longer relevant.

The state of California has invested quite a lot in developing climate change scenarios all the way out to 2100, so we do have a sense of how precipitation is expected to change. It can be hard for people to get their minds around the idea that we could have more droughts and more floods, but we are going to have more extreme events. As temperatures rise, we are going to have less precipitation as snow and less precipitation as rain. So because California has these good climate projections, the proposal to the California Water Commission is that engineers planning for these dam projects should be using these future climate scenarios in their planning, not only historic data.

Eric, in terms of the new projects that are in the works to increase California’s water storage capacity, I’m wondering, this winter’s heavy rain aside, do we actually produce as much water as these expanded storage facilities plan to hold? Would building more help reduce flood risk?

The issue is the case of diminishing returns. Since we’ve already built this network of more than 1,400 dams and reservoirs in the state, all the economical sites have been taken. So with additional surface storage, you don’t get the bang for the buck. There are six big surface projects under serious consideration right now in the state [These include the Sites reservoir to hold water diverted from the Sacramento River, the Temperance Flat Dam on the San Joaquin River, expanding Los Vaqueros Reservoir in Contra Costa to hold water diverted from the San Francisco Bay-Delta, and raising the height of Shasta Dam on the Sacramento River.] But if you look at the yield of even the six big ones, the cost of [building them] would be over $10 billion and the yield is less than 2 percent of our total statewide water use per year. It’s hard to imagine that we can’t come up with more creative and innovative ways to spend that kind of money on smarter water solutions.

Can you explain how come the storage capacity will increase by only that little bit?

It’s the yield figure. People ask how much a new reservoir will hold, but the real figure to look at is the yield. As in what’s the [water] yield on an average year? It’s not going to fill every year, and you also have to maintain flood capacity in a reservoir, so you can’t just fill it to the brim and have it sit there, as we have just learned very vividly with the Oroville situation. So what planners look at is the yield. And we just took the numbers from their analyses, from the bureau of reclamation and the department of water resources and whoever it is that’s putting forward the project, and used their numbers and added up the yield numbers for these facilities, and it’s just really pathetic.

There have been several reports that show cost effective and environmentally sensitive solutions that would yield much more water for California than all of the proposed new and expanded dam projects combined. Deborah, could you elaborate on that?

Yes. The additional water supply from new projects is quite small and as we have seen in the drought of the last five years, is that the way we are making up for that is using groundwater. Groundwater is a huge resource in California but we are also mining that water. But another way of capturing precipitation is groundwater recharge. So rather than building storage on rivers, we can store it underground, and there are ways we can then manage surface and groundwater together – that’s called “conjunctive use”. We also have tremendous opportunities still for water conservation in the state. During the drought years we really focused a lot on urban water conservation because people could adapt quickly – you know, they can choose to stop watering their lawns, but irrigated agriculture still uses the huge majority of the water in California and there’s tremendous opportunity for water conservation in the agriculture sector. Conservation can yield more than 2 percent of our water supply.

Could you elaborate a little bit on how we could reduce water use in agriculture?

Moore: It’s a huge topic but I can give some details. There’s everything from simple measures like leveling the land so that when you flood it – which is a very low tech way of irrigating — the water can easily spread and not pool and puddle; there are areas where we can line canals so that there’s not as much seepage; there’s timing of when you water so that you, just like when you are thinking of watering your lawn, you’re only doing it when the soil needs it; there’s all kinds of new information coming out about how to better use compost and soil amendments to hold more soil moisture, also helps the carbon sink (that’s another whole topic); there’s drip irrigation; there are choices we can make to lower high water using crops – California still grows a lot of alfalfa hay, for example, which is water-intense crop.

So there’s a huge array of cost effective measures that agriculture can use to reduce overall water use, and often it’s good for the farmers as well.

Given climate science, given that it seems to be pretty common knowledge that there are many other low-cost effective ways to save and store water, why is California still focused on building more dams? Eric, could you talk about who is really benefitting from these projects?

We use a term called “OPM,” it stands for “Other People’s Money.” If a water purveyor or irrigation district can get a new reservoir built with other people’s money or taxpayer’s dollars, why not? Even if the extra water they get is a small amount.

Another reason is there’s a lack of imagination and innovative thinking, and sort of going to a just knee-jerk twentieth-century reaction, which is: Oh we are having a drought? We are having severe floods? What do you do, you build something. So we build something without looking under the hood and figuring out what’s really going on here and how to fix it better.

And then there’s money in politics. The ag industry lobby is very powerful in local state and federal levels and so we are dealing with that too.

And finally, it’s [lack of] education. A lot of people don’t know where their water comes from. Knowing where your water comes from, knowing how water is used in California, Deborah said, more than 80 percent of our water goes to agriculture. So yes, we need to take personal action in our homes and businesses but we also really need to ensure that we, as a state, are doing all we can to use water more efficiently. I think knowing that and people calling for reform and action is going to be critical. We need the public voice to be in this debate, calling on state and federal regulators to invest in these innovative water solutions. And when they hear from people that’s going to help a lot.

I’d love to point out the difference that we are not talking about taking water away from agriculture, what we are really talking about is focusing on efficiency.

Eric, I believe Friends of the River has put out a call for action for our legislators and water management agencies. Do you want to briefly outline these for us?

We have asked them to identify unsafe dams and levees and shore them up or tear them down; Invest in flood-control projects that work with nature to maximize public safety, as the Yolo Bypass does — it is the only reason Sacramento wasn’t evacuated on Sunday night; use sustainable water supply and efficiency solutions that reduce risks associated with over-relying on dams for both flood control and water supply. Research by the Pacific Institute has shown that California could save up to 14 million acre-feet a year of untapped water through water saving practices, recycling and storm water capture. Realizing just 10 percent of this potential would increase our water supply by twice as much as the proposed new dams.

Moore: I would like to add that when we are considering infrastructure investments, we make sure that climate projections and climate science are included in that. Last year, California passed a new law, AB 2800, that established a climate-safe infrastructure working group comprising engineers, architects and climate scientists to develop recommendations for best practices to integrate the effects of climate change into all future state infrastructure design and construction. We hope that the working group will help bridge the gap between climate science and engineering design.